The present invention pertains to fabrics. More particularly, the present invention is directed to an additive-free fabric for texturing the surfaces of hard disk drives.
In the manufacture of storage media, such as hard disks (in hard disk drives), the surfaces of such disks must be textured to provide a surface that is smooth and free of defects. As the storage capacity of these disks increases, so does the manufacturing specifications for the disk surface.
Nylon is a popular material that is used for the fabric for providing a textured surface for the disks. Nylon fiber that is manufactured for fabrics is typically spun from polymer that incorporates titanium dioxide (TiO2) at varying levels in the melt during extrusion and pelletizing. The additive is used to provide processing ease, rheology characteristics, light inhibition, and for delustering.
Additive free fibers are known, however, these fibers are near transparent and possess a high degree of shine, both of which are undesirable for general fabric use. As such, these full bright fibers are used only in specialty applications.
It has been found that scratching of finely textured metal media that is used in the manufacture of hard disk drives (e.g., Winchester Drives) is becoming an increasing problem as the surfaces become smoother and smoother, falling below 5 angstroms.
Minute scratches that were not problematic at higher roughness averages create high rates of failure with state of the art recording media. It has been found that using available texturing tapes, without the abrasives used to achieve a textured surface, creates fine scratches similar to those seen on failed disks. It is believed that the titanium dioxide used in the fiber is a causative factor.
Known fabrics use standard titanium dioxide filled fiber that has been shown to produce high scratch levels. These scratches produced results that created unacceptable surfaces for advanced disk drives of 120 gigabytes per square inch.
Titanium dioxide free fabric may have been used in glass media applications. The reason for using such an additive free fiber in glass media applications is not related to scratching but rather to controlling contamination of the glass surface by abraded fiber. The underlying fiber used in the glass media application was polyester.
Accordingly, there is a need for an additive-free fiber for use in fabrics for disk surface texturing. Desirably such a fabric is based upon known fabrics (fibers) and is readily manufactured. More desirably, use of such a fabric results in reduced surface scratching, providing disk recording capacities commensurate with those that technology permits.